River Water Resources Allocation and Participatory Irrigation
Management in Japan today
OKAMOTO Masami
former Professor of Water Resources Management of Nihon University
part-time Lecturer of Environmental Law, Law School of Nihon University
1. Introduction
Japan’s experience will be introduced as one of the basis for the comparative
discussions on the subjects mainly focused here, which are water resources allocationand Participatory Irrigation Management.
Rice-paddy irrigation for small farms in the monsoon area in the tropical region arethe main target here. As the control for comparative discussions, some categories orclassifications are considered; such as humid(H) vs semi-arid(A), tropical(Tr) vstemperate(Tm), small farm(S) vs large farm(L), diversion(D) vs tank-fed(T), andnatural river flow(N) vs reservoir-fed(R).
Afghanistan(Af)A,Tm,S,?, N

India(I)

H,Tr, S,T,R

Thailand(T)

H,Tr, S,D,N

Cambodia(C)H,Tr, S,?, N

Philippine(P)H,Tr, S, D,R

Korea(K)

H,Tm,S,D,R

Japan(J)H,Tm,S,D,R

Australia(Au)A.Tm,L,D,R

2. Main Subjects ;THE major subjects here discussed are as follows;
1) River water resources allocation
2) Participatory Irrigation Managementin Japan today
There are two kinds of water resource such as;1) Ground water: private property; stable but less availability in quantity
2) River water: public property; fluctuating but more availability in quantity
3. Water Rights System in Japan
River water resources allocation are managed, and river flow conditions (both floodsand low flow) are controlled and regulated by the National Government.

Government Permission is indispensable for water users’ diversion of river water.
Buying and selling, borrowing and lending between users are forbidden, because river
flow water are “national” or “public” water, which cannot be owned by anyone as
his/her property.
River water resources allocation in Japan today is administered by the National
Government through the legal systems,” Water Rights” since 1896.
Existing diversions, almost most of which were for irrigation of rice-paddy, wereregarded as already “permitted” water rights.
Principles of river water resources allocation are “ Appropriative Right: “First in timeFirst in Right”.
Procedure is that potential water users shall apply to the National Government.
A complete application shall include:- The name and address of the applicants- The nature and the proposed place of use- The proposed place of diversion- The location and description of the proposed head works and other works- The amount of the use
for irrigation of rice-paddy, the applied amount of the use changes againststages such as nursery bed~/ puddling and transplanting~/ growing~ etc. andonly in a irrigation (summer) season, not in a off-season- others
Application and Permit fee are not charged in reality.
The Government gives permission to an applicant, when no protests based on alleged
injury to prior rights
4. ”Standard” “Normal” Low Flow:“Standard Low Flow” and “Normal Low Flow” technically defined by the Government isa basis of regulation and control of low flow in river channels in drought.
The definition of standard low flow or normal flow is:
90% exceeding probability of low flow discharge in a river channel
10% risk probability=90% safety probability (occurrence: once-in-ten-years)“Standard low flow” discharge minus “Maintenance flow” discharge is available todiversion of river flow by an applicant.
“Standard low flow” should be more than or equal to Maintenance flow discharge andall of prior right discharges.
- “Maintenance flow” is in-stream flow discharge for environment conservation andothers such as navigation, dilution of polluted water etc
River flows are controlled and regulated by administration of the GovernmentIf available waters are not enough for a new applicant, a reservoir should beconstructed by an applicant’s pay at the order of the Ministry.
In drought, the Ministry officials administer to release stored water in a reservoir orreservoirs to augment low flow in river channels to augment natural river low flow
discharge to keep flow conditions to satisfy maintenance flow and prior rights.
When emergent Drought occurs, and river flow discharge becomes less than standard
low flow, river water resources could be temporarily reallocated by conference of all ofwater right holders, sometimes not in proportion of water rights in quantity.
5. Participatory Irrigation Management (PIM)
Principles or philosophy built in the setting behind the concepts of PIM proposed bystaff of the World Bank are as follows;
1) farmers (stake holders)(water users) should participate in Operation, Maintenanceand Management (OMM) of Irrigation Systems to establish “democratic” organization(association) of “Water Users” (WUA) of the farmers, by the farmers, for the farmers.
2) Market mechanism:
Beneficiaries should Pay Principle (BPP), in other words no public subsidy for OMM
costs (exceptionally for construction cost internationally)
6. Land Improvement District (LID)= Japanese farmers’ irrigation association＝ Japanese water user-farmers’ association
LIDs were, are and will be established based on Land Improvement Act enforced in1949.

toreplace“(Landowners’)

Irrigation

andDrainage

Association”

or“(Agricultural) Land Consolidation Association” before the War II, and has got a
reputation as the most successful organizations of PIM by their performance
Organizational structure and functions of LIDs are briefed by using the typical modelof a LID shown here for your understanding.
Suppose, a typical LID has 6,000 member-farmers, 5,000 ha beneficial rice-paddy
fields.
Procedures of management are;1) 6,000 farmers elect 700 “representatives” among them by secret voting
one person, one vote. equity! (no discrimination: rich/poor, gender etc. democracy!)2) 700 representatives elect 8 directors among them, who form the Board of Directors
3) A Director General is elected by elected directors
4) The Board of Directors can invite some (1~3) experts as non-member directors
5) The Board employs some staff in their office, who are in charge of OMM works6) Every activities are discussed and decided by the assembly of representatives7) the Board of Directors conducts administrative works of OMM on a basis of policies

made and approved by representativesMajor functions of LIDs are;1) Application of a construction project to the MAFF
MAFF=Minister of Agriculture, Forestry and Fisheryso-called “construction project” in Japan embraces many different kinds ofprojects

suchasconstruction,reconstruction,replacement,upgrading,rehabilitation.
2) Repayment for Construction Cost, 80~90 percentage of which is subsidize(the other 10~20% will be levy on member-farmers)
Typical Subsidy Ratio is shown below;
project conducted byNational G.

Local G.

Municipality (city/town)

LID (%)

National Government

60201010

Local Government

502512.512.53) OMM of constructed irrigation facilities such as a diversion dam, irrigation canals,pump(s) etc, OMM of which are handovered/transferred from the Government to a
LID without “official” public subsidy
cf. Since foundation of WUAs before the War II, OMM has been done by land-owneror tenant-farmers by their own pay and labor, paying land tax or tenant fee before
LIDs.
rf. Cost of major repair originated from severe natural disaster such as anearthquake and floods are fully subsidized by National Government4) Charge membership fee (water charge) on his/her paddy fields on area basis
7. Income of a LID
1) membership fee (typically ¥50,000= US$450/year/ha-rice paddy=3~5 % of the yield)
rf. typical paddy yield: 7~8 tons/ha/year(one crop)2) charges, rent etc. upon persons for their using LID’s operated facilities such as
canals for their sewage and runoff drainage
3) “detour” public subsidy for OMM costs of a LID
8. Typical diversion requirements for rice-paddy:
for predominant river flow diversion systems; 20~30 mm/day
for few tank-fed systems; 10 mm/day

Management Project

Construction ProjectLand Improvement Projectnew construction
reconstruction
upgradingrehabilitation
Manicipality(City, Town, Village)

Local
Government

NationalGovernment

Subsidy ?
Application ofConstruction Project
Informal and Traditioanal
Irrigation Organization

Approval

Land Improvement District
Directore General

Federation ofSecondary canal
associations

Maincanal

Federation of
Tertiary canal
associations

Secondarycanal

Representativesof MuraTertiary
canalQuarterly
canal

Top down

Subsidy

TechnicalSupport

Construction
CostConstruction
Project

Board ofDirectors

hire

Bottom up
Staffselection
General Assembly

OM(M) Cost
Operation
MaitenanceManagement

Representatives

RegularAssociation Feeelection

Special
Association Fee

Members (Farmers)
Mura (Rural community)

Hand Over ofManagement
Irrigation Facilities
Diversion Dam / Barrage, Canal, Pump

complete